Fish Feeds in Aquaponics and Beyond: A Novel Concept to Evaluate Protein Sources in Diets for Circular Multitrophic Food Production Systems

With the general objective of optimizing internal nutrient recycling, circular multitrophic food production systems, e.g., combining fish, plant, and insect larvae production, rely on quality composition sustainable nutritional inputs. Therefore, differences in dissolved solid excretion patterns produced by Nile tilapia (Oreochromis niloticus) reared recirculating aquaculture systems (RAS) with 5% daily water exchange fed black soldier fly meal (BSFM), poultry by-product (PM), blood (PBM) fish (FM) as single protein sources were investigated to evaluate potential for creating specific meal-free diets. Fish FM PM diet showed significantly best (p < 0.05) among each other similar > growth performance (specific rate (SGR): 2.12 ± 0.04/2.05 0.11; feed conversion ratio (FCR): 0.86 0.03/0.92 0.01), whereas PBM caused reduced (SGR: 1.30 0.02; FCR: 1.79 comparison FM/PM well BSF 1.76 0.07; 1.11 0.05). The resulted a faster increase higher nitrogen phosphorus levels, while accumulation elevated levels potassium, magnesium, copper. feces highest density (gross energy, crude protein, amino acids) but overall much lower water. Results are discussed regard implications developing systems.